Gray Wolf Recovery Precipitates a Species-Specific Trophic Cascade in the Upper Great Lakes Region
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High densities of white-tailed deer throughout eastern North America have been implicated in changing forest community structure and composition. We hypothesized that the recovery of an apex predator, the gray wolf (Canis lupus), in a region affected by deer overabundance could reduce browsing impacts on vegetation via a trophic cascade. We tested this hypothesis by surveying an herbaceous forest understory species sensitive to deer browsing (Polygonatum pubescens) in areas of northern Wisconsin where wolves have re-colonized over the past 20 years. We used a natural experimental framework, surveying populations in areas that lack wolves (nonwolf, n = 3 sites), areas where wolves have been established for 3-5 years (3 sites), and areas where wolves have been established for 9-11 years (3 sites). Each site consisted of five 10m x 10m plots. We compared these populations to plants growing in deer exclosures continuously maintained for 15 years. The number of leaves per plant and percent flowering was recorded for 1,579 plants.
Bouchard, K. A.,
Rooney, T. P.,
Wydeven, A. P.,
& Wiedenhoeft, J. E.
(2009). Gray Wolf Recovery Precipitates a Species-Specific Trophic Cascade in the Upper Great Lakes Region. Ecological Society of America Annual Meeting.